Absorbent articles having lotion applied on, for example, the topsheet have been known within the area for quite some time now. By applying lotion on an absorbent article such as a diaper, an incontinence product, a sanitary napkin or the like, added value is given to the product.
As described in WO 96/16682, the lotion, or similar product, could be placed on the topsheet of a diaper. In this manner, the lotion is said to add barrier properties to the skin, reducing the irritation caused by contact with faeces.
Further back in time, similar use of lotions was known, for example, through U.S. Pat. No. 3,896,807, which describes how the surface of a diaper can be furnished with an emulsifiable phase which upon exposure to moisture will form a water/oil (W/O) or oil/water (O/W) emulsion. During use of the product, the emulsion will transfer to the user's skin and will act as a vehicle for adding skin caring substances to the user's skin.
In earlier published literature, several examples are given of how to apply the lotion on absorbent articles.
In WO 96/16681 spraying, printing (e.g. flexographic printing), coating and extrusion are mentioned as examples of application methods. With the spray technique, it is said to be possible to spray patterns having a dimension of 9×18 cm.
In WO 98/24390 and WO 99/45974, slot coating, extrusion coating, gravure coating, spraying and printing are mentioned. The lotion can be applied in stripes, squares, dots or spirals.
WO 00/48544 more thoroughly describes the techniques used to apply lotion on absorbent articles. More specifically, spraying is described. When spraying, the lotion is propelled through a nozzle by means of air. However, it can also be propelled through the nozzle substantially without the use of air. Further, it is described that the nozzle can be mechanically manipulated during spraying to form patterns such as spirals, squares, stripes or circles. In order to achieve a desired pattern such as a square, the nozzle itself needs to be altered. It is also stated that the stripes have a minimum with of 0.1 inches.
The existing spray technique offers some advantages to the producer of absorbent articles wanting to give added values to absorbent articles. However, several disadvantages still exist that the prior art has failed to remove.
When the lotion is sprayed through the orifice of the nozzle at high speed, it is subjected to a high amount of stress. The stress is not only purely mechanical stress, but is also caused by pressure differences. This causes the lotion to turn into an aerosol fully, or partly, which greatly affects the quality of the applied pattern and the flexibility of the process.
Even if it is possible to make patterns such as spirals, stripes or circles, the applied pattern becomes diffuse in the periphery and the aerosolised spray string makes it difficult to add lotion in an exact manner.
The nozzle of the spray head needs to be in close proximity to the sprayed surface. This prevents the spray string from being spread too much in an uncontrolled manner. However, this is a severe limitation to process flexibility since even if the slightest amount of aerosol is formed, it will complicate the handling and the flexibility of the process.
The fine droplets from the aerosol which lie in the periphery of the sprayed string can easily be sucked down into the absorbent core by the capillary forces of the absorbent core or an acquisition layer. This reduces the absorbent capacity and the acquisition rate of the absorbent article. Accordingly, it is important to keep the lotion on the surface of the absorbent article.
From a process point of view, it is difficult to handle aerosols when manufacturing absorbent articles. Reducing the amount of aerosol vastly reduces the required amount of cleaning and maintenance of the production equipment.
Consequently, there is a need for a method of applying lotion to absorbent articles in a simple and efficient manner. Hence, it is an object of the current invention to solve the above-mentioned problems and to provide an improved method for applying lotion to absorbent articles. It is also an object of the invention to provide an absorbent article having lotion arranged in a well-defined application pattern.